Visible crew/equipment: After Phoebe fails to convince herself to push the elevator button she bumps into Les anyway, and when Phoebe tells him she's a "busy little bee" the camera angle changes, and we can see the pink and white T-marks on the floor. (00:10:00)
Visible crew/equipment: After Leslie decides not to ring the manor's doorbell he turns around, and when he sees Phoebe as she walks up the steps, the reflection of crew members is visible on the car window behind Phoebe. Then as Phoebe and Les are talking, we also see the reflection of the boom mic on the window of the car in the driveway. (00:40:15)
Answer: That was a mistake in the series.
Also, the episode is called 'Babies First Demon' and this alone tells us that it's Wyatt's first time in the field (so to speak) and as the sisters say, they've done a good job of clearing up their own magical messes so far. Nobody really knows how advanced Wyatt's powers are, or will become. That's why the cleaners appear, to nip things in the bud. The Cleaners didn't want to chance that the sisters could clean Wyatt's magic up, just incase they couldn't. Therefore intervening themselves, just in case.